Hadith 3:636

Narrated Abu Mas'ud:

There was an Ansari man called Abu Shu'aib who had a slave butcher.
Abu Shu'aib said to him, "Prepare a meal sufficient for five persons
so that I might invite the Prophet besides other four persons." Abu
Shu'aib had seen the signs of hunger on the face of the Prophet and so
he invited him. Another man who was not invited, followed the Prophet.
The Prophet said to Abu Shu'aib, "This man has followed us. Do you
allow him to share the meal?" Abu Shu'aib said, "Yes."